Encapsulation of components and a low energy circuit for hazardous locations

Patent metadata

Field	Value
Publication number	US-9559517-B2
Application number	US-201414488150-A
Country	US
Kind code	B2
Filing date	Sep 16, 2014
Priority date	Sep 16, 2014
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

Embodiments of the disclosure provide an encapsulated compressor overload, an encapsulated compressor relay start, an encapsulated head pressure control switch and a wiring diagram for a circuit for air conditioning units which prevent gases from being ignited by means of encapsulating sparking components, use of solid-state switching devices, and/or wiring circuits in such a way that open contacts do not contain enough energy to produce a spark capable of igniting the atmosphere.

First claim

The invention claimed is:

1. An encapsulated compressor overload for use with air conditioning or refrigeration systems in a hazardous location where flammable gases or vapors may exist, the encapsulated compressor overload comprising:
a compressor overload comprising:
a thermal sensor;
at least one overload terminal each attached to one of one or more wires;
a thermally conductive base bracket located next to the thermal sensor to allow the thermal sensor to sense temperature through the base bracket; and
a disc coupled to the base bracket; and

encapsulation material forming an air tight cover surrounding the compressor overload and allowing the one or more wires and the base bracket to extend through the air tight cover, such that sparks created by the compressor overload are completely contained within the encapsulation material and prevented from coming into contact with the flammable gases and vapors.

2. The encapsulated compressor overload of claim 1 wherein the base bracket comprises a bottom surface which is not covered by the encapsulation material and is flush with the encapsulation material.

3. The encapsulated compressor overload of claim 1 wherein the encapsulation material is a polyurethane resin and is about one-quarter inch thick.

4. The encapsulated compressor overload of claim 1 wherein all components of the compressor overload which have the ability to become electrically live are substantially covered with a silicone sealant.

5. The encapsulated compressor overload of claim 4 wherein the silicone sealant has a minimum thickness sufficient to meet the minimum flammability rating requirements of UL 94 V-0.

6. An apparatus for adapting a non-hazardous location air conditioner for use in an environment in which flammable gases or vapors are present, the apparatus comprising:
an encapsulated compressor overload electrically connected to a compressor of the air conditioner, the encapsulated compressor overload comprising:
a compressor overload comprising:
one or more components capable of sparking during operation; and
a base bracket; and

a first encapsulation material forming an air tight cover surrounding the one or more components of the compressor overload, such that sparks created by the compressor overload are completely contained within the first encapsulation material and prevented from coming into contact with the flammable gases and vapors, the base bracket of the compressor overload extending through the first encapsulation material.

7. The apparatus of claim 6 , wherein a bottom surface of the base bracket is not covered by and sits flush with the first encapsulation material, wherein the base bracket is thermally conductive, and wherein the one or more components of the compressor overload include a thermal sensor located next to the base bracket and sensing temperature through the base bracket.

8. The apparatus of claim 6 , wherein the one or more components of the compressor overload include an overload terminal attached to a wire that extends through the first encapsulation material.

9. The apparatus of claim 6 , further comprising an encapsulated compressor start relay electrically connected to the compressor of the air conditioner, the encapsulated compressor start relay comprising:
a compressor start relay having a plurality of relay terminals each attached to a corresponding wire of a plurality of wires; and
a second encapsulation material forming an air tight cover completely surrounding the compressor start relay and allowing the plurality of wires to extend through the air tight cover, such that sparks created by the compressor start relay are completely contained within the second encapsulation material and prevented from coming into contact with the flammable gases and vapors.

10. The apparatus of claim 9 , further comprising an encapsulated pressure switch in electrical communication with the compressor of the air conditioner, the encapsulated pressure switch comprising:
a pressure switch having one or more components capable of sparking during operation;
an air tight tube surrounding the one or more components of the pressure switch and having a first edge and a second edge; and
a sealant material applied to each of the first edge and the second edge, creating an air tight seal around the one or more components of the pressure switch that prevents sparks of the pressure switch from coming into contact with the flammable gases and vapors.

11. The apparatus of claim 10 , wherein the one or more components of the pressure switch include a body portion surrounded by the tube, the pressure switch further comprising:
a connector extending through the sealant material at the first edge of the tube; and
one or more wires extending through the sealant material at the second edge of the tube.

12. The apparatus of claim 10 , wherein each of the encapsulated compressor overload, the encapsulated compressor start relay, and the encapsulated pressure switch is individually sealed off from each other sparking components of the air conditioner.

13. The apparatus of claim 9 , wherein one or both of the first encapsulation material and the second encapsulation material are a polyurethane resin.

14. The apparatus of claim 9 , wherein one or both of the first encapsulation material and the second encapsulation material are about one-quarter inch thick.

Assignees

• Stammer Scott Dean
• Her La
• Martin William
• Hoffman Enclosures Inc

Inventors

• Stammer Scott Dean
• Her La
• Martin William

Classifications

• H01H37/04

  Bases; Housings; Mountings {(H01H37/5427 takes precedence)} · CPC title

• H01H9/04

  Dustproof, splashproof, drip-proof, waterproof, or flameproof casings · CPC title

• F25B31/00 Primary

  Compressor arrangements · CPC title

• H01H45/14

  Terminal arrangements · CPC title

• H01H9/042 Primary

  Explosion-proof cases · CPC title